Boot Size :5 US / 38 Euro6 US / 39 Euro7 US / 40.5 Euro8 US / 42 Euro9 US / 43 Euro10 US / 44.5 Euro11 US / 45.5 Euro12 US / 47 Euro13 US / 48 Euro Alpinestars Tech 2 Boots Black. Part of the Alpinestars Tech Series family of technical riding boots, the Tech 2 shares the same structural strength and foot protection of the rest of full-height line-up, with a lower cut design for greater flexibility and comfort on a mini-bike or ATV riding.